Iridium Spark Plugs Need a Precise Gapping Tool

by | Nov 1, 2022 | 0 comments


In a sense, spark plugs are an engine’s heartbeat, critical to optimal engine performance—if they’re gapped properly when they’re installed.

As you’re aware—but your customers might not be—properly gapped plugs allow the engine to literally fire on all cylinders, while the wrong gap will not create the proper ignition and engine performance, regardless of vehicle.

When replacing your customers’ spark plugs, you can help them understand that because gap distances are measured down to the tenth of a millimeter, or four one-thousandths of an inch, it’s crucial to be extra careful when checking or setting the gap in each plug. If the gap is too small, the flame kernel will not be able to properly expand. If it’s too big, the coil will need too much voltage to fire. In either case, engine combustibility will be incorrect.

The Right Tool to Gap Iridium Spark Plugs  

Today’s spark plugs are precision-built products, so even the smallest adjustments will change their performance. This is especially true for customers who run iridium plugs.

Iridium spark plugs are designed to deliver more than 100,000 miles of reliable ignition and fuel efficiency, but improper gapping can easily damage the sensitive iridium electrodes. To avoid this, the gap should only be checked with the right tool.

Like spark plug metallurgy, gapping gauges have been adapted for more focused performance over time. 

Feeler gauges or coin-style (ramp-style) gauges aren’t as well-suited for precision plugs like iridium because of the risks of damage to the iridium finewire electrode. Because of this, it became clear over the years that a more precise gapping tool like a wire loop gauge is recommended for this task.

Wire loop gauges are not only accurate, but they minimize the chances of incidental damage to the plug when used correctly. This makes it the preferred gapping tool for shop techs to use when setting customers up with the right ignition products for their needs.

Autolite Iridium Ultra® Spark Plugs are the highest performance offering from Autolite® and provide the same precision and reliability of an engineered OE replacement plug. Iridium Ultra® plugs feature a laser-welded iridium finewire center electrode for optimal fuel efficiency, acceleration, and focused ignitability for long-lasting performance.

Autolite® has been the trusted developer of spark plugs for over 85 years. We have done the research and put in the hours to enhance the performance, durability, and ignitability of plugs for domestic and import engines.

Explore the benefits of our most advanced products like our iridium spark plugs at 


Submit a Comment

Your email address will not be published. Required fields are marked *